I’m thinking of Jacqueline Kennedy today, on what would have been her 89th birthday. While she was “Jackie” to the world, I always called her “Mrs. Kennedy,” and she always called me “Mr. Hill.”

I was fortunate to be with her for four years–from November 1960 to November 1964. As I wrote in my 2012 book Mrs. Kennedy and Me, at first, being a Secret Service agent on the First Lady’s Detail was the last place I wanted to be. It was like being on the second team. I wanted to be where the action was–and that had always been with the president. As it turned out, I had the best assignment of all.